fix: throw NullReferenceException for element access (#414)

riok · May 9, 2023 · 78b2736 · 78b2736
1 parent 98a44a0
commit 78b2736
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Showing 2 changed files with 16 additions and 3 deletions.
diff --git a/src/Riok.Mapperly/Emit/SyntaxFactoryHelper.cs b/src/Riok.Mapperly/Emit/SyntaxFactoryHelper.cs
@@ -77,6 +77,12 @@ public static ExpressionSyntax NullSubstitute(ITypeSymbol t, ExpressionSyntax ar
             NullFallbackValue.Default => DefaultLiteral(),
             NullFallbackValue.EmptyString => StringLiteral(string.Empty),
             NullFallbackValue.CreateInstance => CreateInstance(t),
+            _ when argument is ElementAccessExpressionSyntax memberAccess
+                => ThrowNullReferenceException(
+                    InterpolatedString(
+                        $"Sequence {NameOf(memberAccess.Expression)}, contained a null value at index {memberAccess.ArgumentList.Arguments[0].Expression}."
+                    )
+                ),
             _ => ThrowArgumentNullException(argument),
         };
     }
@@ -165,6 +171,13 @@ public static ThrowExpressionSyntax ThrowNullReferenceException(string message)
         );
     }
 
+    public static ThrowExpressionSyntax ThrowNullReferenceException(ExpressionSyntax arg)
+    {
+        return ThrowExpression(
+            ObjectCreationExpression(IdentifierName(NullReferenceExceptionClassName)).WithArgumentList(ArgumentList(arg))
+        );
+    }
+
     public static ThrowExpressionSyntax ThrowArgumentOutOfRangeException(ExpressionSyntax arg, string message)
     {
         return ThrowExpression(

diff --git a/test/Riok.Mapperly.Tests/Mapping/EnumerableTest.cs b/test/Riok.Mapperly.Tests/Mapping/EnumerableTest.cs
@@ -35,7 +35,7 @@ public void ArrayOfNullablePrimitiveTypesToNonNullableArray()
                 var target = new int[source.Length];
                 for (var i = 0; i < source.Length; i++)
                 {
-                    target[i] = source[i] == null ? throw new System.ArgumentNullException(nameof(source[i])) : source[i].Value;
+                    target[i] = source[i] == null ? throw new System.NullReferenceException($"Sequence {nameof(source)}, contained a null value at index {i}.") : source[i].Value;
                 }
 
                 return target;
@@ -82,7 +82,7 @@ public void ArrayOfNullablePrimitiveTypesToNonNullableArrayDeepCloning()
                 var target = new int[source.Length];
                 for (var i = 0; i < source.Length; i++)
                 {
-                    target[i] = source[i] == null ? throw new System.ArgumentNullException(nameof(source[i])) : source[i].Value;
+                    target[i] = source[i] == null ? throw new System.NullReferenceException($"Sequence {nameof(source)}, contained a null value at index {i}.") : source[i].Value;
                 }
 
                 return target;
@@ -129,7 +129,7 @@ public void ArrayCustomClassNullableToArrayCustomClassNonNullable()
                 var target = new global::B[source.Length];
                 for (var i = 0; i < source.Length; i++)
                 {
-                    target[i] = source[i] == null ? throw new System.ArgumentNullException(nameof(source[i])) : source[i];
+                    target[i] = source[i] == null ? throw new System.NullReferenceException($"Sequence {nameof(source)}, contained a null value at index {i}.") : source[i];
                 }
 
                 return target;